Effects of salicylate on sound-evoked outer hair cell stereocilia deflections

Pflugers Arch. 2015 Sep;467(9):2021-9. doi: 10.1007/s00424-014-1646-4. Epub 2014 Nov 14.

Abstract

Hearing depends on sound-evoked deflections of the stereocilia that protrude from the sensory hair cells in the inner ear. Although sound provides an important force driving stereocilia, forces generated through mechanically sensitive ion channels and through the motor protein prestin have been shown to influence stereocilia motion in solitary hair cells. While a possible influence of prestin on mechanically sensitive ion channels has not been systematically investigated, a decrease in transducer currents is evident in solitary hair cells when prestin is blocked with salicylate, raising the question of whether a reduced prestin activity or salicylate itself affected the mechanotransduction apparatus. We used two- and three-dimensional time-resolved confocal imaging to visualize outer hair cell stereocilia during sound stimulation in the apical turn of cochlear explant preparations from the guinea pig. Surprisingly, following application of salicylate, outer hair cell stereocilia deflections increased, while cochlear microphonic potentials decreased. However, when prestin activity was altered with the chloride ionophore tributyltin, both the cochlear microphonic potential and the stereocilia deflection amplitude decreased. Neither positive nor negative current stimulation abolished the bundle movements in the presence of salicylate, indicating that the observed effects did not depend on the endocochlear potential. These data suggest that salicylate may alter the mechanical properties of stereocilia, decreasing their bending stiffness.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acoustic Stimulation
  • Animals
  • Cochlear Microphonic Potentials / drug effects
  • Cochlear Microphonic Potentials / physiology
  • Electrophysiology
  • Female
  • Guinea Pigs
  • Hair Cells, Auditory, Outer / drug effects*
  • Hair Cells, Auditory, Outer / metabolism
  • Male
  • Mechanotransduction, Cellular / drug effects
  • Mechanotransduction, Cellular / physiology*
  • Microscopy, Confocal
  • Proteins / metabolism
  • Salicylic Acid / pharmacology*
  • Stereocilia / drug effects*
  • Stereocilia / metabolism

Substances

  • Pres protein, Cavia porcellus
  • Proteins
  • Salicylic Acid